This question already has an answer here:
A recent gofundme page is seeking to crowd fund Trump's proposed border wall. Assuming that this is a genuine attempt to raise the money rather than a scam or political stunt, is it even possible for an indidividual or group of individuals to donate money to the US Government and have it ear marked for a specific purpose? I have no doubt that you can donate to the us government, but that comes with two specific caveats:
Money deposited into this account is for general use by the federal government and can be available for budget needs.
These contributions are considered an unconditional gift to the government.
In short, is it possible to donate money to the government for a specific purpose and get anything better than a promise that it will be used for what you say it will?